Worm farms are a fast and organic way to make compost and can help to improve the end result. Any compost pile relies on worms and insects to decompose food fully. Creating your own dedicated worm farm at home just gives nature a push in the right direction.
Whether you’re searching for tips on building your own DIY worm farm at home or are looking for professional worm farms that are built to last, we’ve got everything you need to know below.
1. Subpod Outdoor Compost Bin & Worm Farm
2. Urbalive Worm Farm Compost Bin
3. Biogize Compost Worm Tower
4. Hungry Bin Worm Farm Compost Bin
5. Maze Worm Farm Composter
6. Redmon For Kids Worm Farm
7. Worm Factory 360
What is a Worm Farm?
Worm farms are self-contained compost units, which introduce worms, or encourage them in from the earth, in order to speed up the production of compost.
While worm farms can be made at home from very humble materials, shop-bought worm farms are available in a wide array of designs.
Some are simple, suspended canopies, using layering to create logical decomposition, while others are buried with ventilation holes to allow worms to move, and for compost to breathe.
What Do Worms Eat?
Worms digest fallen vegetation, and rotting organic matter, into a form of compost called worm castings. Worm castings speed up the breakdown of food waste and leaf litter.
Compost is at its best when it has begun the process of breaking down, and is a mix of part rotted organic matter and humus (the term given to fully rotted organic matter, which has essentially become moisture retentive soil).
Worms speed up the production of humus, but help to retain key nutrients like nitrogen, potassium and phosphorus in the compost mix.
How to Build a Worm Farm
Building a DIY worm farm is really quite straightforward. All you need is a bucket, a drill, and some kitchen scraps. You can speed the process up with specially purchased worms, but the worms in your own soil will eventually find your worm farm.
Below, we’ve got instructions on how to build two types of worm farm, plus a guide to picking the best worms for your worm farm, and how to feed them.
Building a Worm Composter
Worm composters aren’t strictly worm farms, as worms have access in, and out, of the compost bin. Compost happens at a slightly faster than normal rate, and you won’t get a sump full of liquid fertilizer to use at the base of your bin.
However, worm composters are worth considering for a quick fix in the garden, where you don’t have space for a larger worm farm or compost bin system.
To build a simple worm composter:
- Find a plastic bucket with a lid, or use an old dustbin.
- Dig a hole, half the depth of the container.
- Drill plenty of holes all over the side of the container (4” apart in a grid).
- Drill five drainage holes in the base (this allows worms in, and moisture out).
- Place your container in its hole, and backfill around the outside.
- Add a thin layer of garden soil back into the base.
- Add kitchen scraps and garden waste into the bucket, with the lid on.
- Try to add organic matter in layers:
Layer 1: soil
Layer 2: kitchen scraps
Layer 3: Grass clippings/garden waste
Layer 4: Straw/paper/dry waste
- Regularly add garden and kitchen waste.
- When your composter is full, turn it over with a garden fork. The base will be fully composted, and the air holes will encourage worms thanks to better aeration from above.
DIY Worm Farm Guide
For a more heavy-duty worm farm you can build at home, you’ll need a few more tools and a decent amount of space. The principle of a worm farm is that worms eat, digest, and excrete garden and kitchen waste.
This produces a mix of wet and dry waste. The dry waste makes great compost, while the liquid product of a worm farm is a great, high nitrogen fertilizer you can use straight on your pots or veg patch.
To build your own worm farm, you will need:
- 3-4 stackable boxes (plastic is best, but timber works)
- Straw / Hay / Dry grass clippings
- 1 stand (we used an old chair base, but anything taller than your water can is fine)
- 1 tap
- 2-3 Cotton / Linen / Wool sheets
- Start by preparing a base. You can place the base over any ground provided it is level or the legs are set in place so the farm won’t move. We used an old chair base, but anything that holds the bottom of the worm farm higher than a watering can.
- Drill a hole on the front side of the bottom stacking box, large enough to fit a tap. This will become your sump tray.
- Screw your tap into the hole.
- Drill holes in the lid of the bottom stacking box.
- Drill holes in the bases and lids of your other boxes. These allow worms to move between boxes, and moisture to drain into the sump.
- Stack all boxes on top of each other, laying cotton, linen, or wool sheeting to the base of each box. This means worms and moisture can move between, but organic waste stays in place.
- Fill the bottom box with a mix of soil, kitchen waste, and grass clippings.
- Add worms.
- Add kitchen and garden waste to each box until they are full (starting from the bottom up).
Drain the sump tray in your DIY worm farm regularly and use it to feed container plants. Leave 2-3 months per box for rotting. When the bottom box has finished rotting down, use it in the garden, and move it to the top.
What are the Best Worms for a Worm Farm?
Red wigglers, or red worms, are the best worms for a worm farm. They are voracious feeders and quickly work through kitchen waste, turning it into fertile worm castings for the garden.
Another big benefit of red wigglers is that they breed relatively quickly, so you don’t need to worry about replenishing your worm farm’s population as they will colonize every level.
Where to buy worms for a worm farm
You can buy red wigglers online easily, but make sure you get them from a reputable source. Uncle Jim’s worms are a great supplier, with excellent packaging for live garden products.
For a beginner’s worm farm, try their box of 500 red wigglers, which is more than enough to get started on a small multi-level worm farm.
How to Maintain a Worm Farm
Now you’re set up and ready to go, it’s important to keep your worm farm (and worms) happy. Worms won’t dig in poorly aerated damp soil but are just as unhappy in loose, dry compost.
Below, we break down the important considerations for maintaining a worm farm:
A really basic necessity for any worm farm is moisture. Don’t allow your worm farm to become waterlogged as stagnant water can suffocate worms, and ruin your compost.
If your worm farm is visibly dry, water it lightly by pouring half a watering can into the top. If your worm farm is too wet, drain the sump, and add dry materials, like hay, newspaper or shredded cardboard.
Worms can cope with most temperature conditions, but they do most of their work at around 60F, so place your worm farm somewhere sunny, where it can warm up without baking.
Higher temperatures speed up the decay of food waste too and help to maintain good moisture and humidity levels.
Anaerobic compost is basically impossible. Organic matter needs oxygen to break down, and the creatures in your soil need to breathe. Maintaining a good mix of food waste, garden waste, and dry materials helps air to move through rotting waste.
The easiest way to aerate your worm farm is to add waste in layers. Add a sprinkle of soil to feed the farm with good bacteria, followed by kitchen waste, then hay (or paper), then grass clippings. Thin layers like this allow worms to move around and breathe.
How often to feed a worm farm
Unless you have an industrial-scale worm farm, you’re not going to use up all your kitchen waste, but you can add a good portion of kitchen scraps and grass clippings each week.
Once a box is full it will usually take 2-3 months to break down into usable worm castings and rotted waste. After a while, you’ll find a rhythm for feeding your worm farm, but each box should generally take 2-3 weeks to fill up.
This should give you a good 2-3 month rotation on a 3-4 tiered worm farm.
Buyer’s Guide to Worm Farms
What to look for When Buying a Worm Farm?
If you don’t fancy building your own, and want to make sure you’ve got the best worm farm possible, there are some incredible designs online. As well as space-saving solutions, there are great mid-range solutions that are easy to maintain and don’t require regular topping up.
Remember that worm farms are designed to hold decomposing waste, so find a good quality plastic worm farm or one with tough synthetic fabrics that can hold up to the weather, and the heat produced by decomposing.
Timber might look good, but it won’t last as long and isn’t as easy to clean.
Different Types of Worm Farms
Choosing the right type of worm farm depends almost entirely on space. If you’ve got a small kitchen garden, adding a massive buried worm farm isn’t practical.
Equally, if you’re producing masses of kitchen waste, a small suspended worm farm can be quickly overwhelmed. Below, we’ve got a guide to each of the main types of worm farm to help you choose:
Worm towers allow for the collection of liquid fertilizer in a sump tray, using a simple tap to pour filtered nutrient-rich water into a watering can or bucket. The tower system also gives access to worm castings and compost faster than buried warm farms or traditional composters.
Worm towers take more maintenance than buried worm farms as they require regular rotations to maintain the health of the farm, the worms, and the compost.
Buried worm farms
Buried worm farms are a low-maintenance alternative, essentially just using garden worms to turn compost and speed up the process slightly.
By burying compost bins, with specially prepared holes for drainage and access, composting is sped up by up to six months. Buried worm farms don’t allow for rotation or easy mixing, and tend to produce denser, wetter compost.
Do you think your kitchen waste is not enough for the types above? Check out Compost grinders which might be just the answer for you.
Best Worm Farm Reviews
Worm Farm Top Picks for 2023
Best Worm Farm - Our Top Pick
Subpod have been around for a few years, and were producing pretty much perfect worm farms from day one. Their latest model goes a few steps further though, with a more compact design and deeper side, plus an improved locking system to keep vermin and pests out of your compost and away from rotting kitchen waste.
If you add even layers of shredded paper and kitchen waste, you can quickly build up a healthy supply of homemade garden compost using the subpod system, which stands out as one of the best worm farms on the market in 2023.
Premium Choice Worm Farm
Vermiculture might not scream contemporary living, but this modern worm farm is designed perfectly to fit into any designer home.
Forget basic kitchen caddies, filling with smelly food waste, and waiting for a week to be carried to the compost. This worm farm gets to work straight away to turn your kitchen waste into beautiful compost and plant food.
Within a few days of setting it up, you’ll have a generous reservoir of liquid plant foods that is easy to extract using the tap at the base of the design, which helps keep its compact form.
Best Value Worm Farm
For a quick worm farm on a budget, you can’t go wrong with this basic worm bin, which buries easily in the garden, and has a tight-fitting lid to keep kitchen scraps safe from vermin.
It’s a far cry from the worm towers in our other reviews, but it works and it's easy to use. If budget is your main consideration this is the best worm farm you’ll find for this price.
Worm Farm Frequently Asked Questions
How often should I check my worm farm?
When you first add worms to your worm farm, check them daily. Worms in worm farms are very active when they are first added.
If you see no changes in the first two or three days, try adding a sprinkle of garden soil, or moving your farm somewhere warmer. When established, check your worm farm weekly.
What should you not put in a worm farm?
Meat, fat, bones, oils, or cooked food should not be put in a worm farm. Adding fats or cooked food attracts vermin and increases moisture to a point that worms can’t cope with.
Oils and fatty acids are also incredibly bad for your soil and garden and can have a lasting impact on wildlife.
Is it ok to have maggots in a worm farm?
Maggots and flies are signs of rotting rather than decomposing, meaning molds, fats and oils are present in your composter. Maggots won’t negatively affect your compost or your worms, but they are a sign that the food waste you are adding is a bad mix.
Should I stir my worm farm?
There is no need to stir your worm farm. If you are worried about anaerobic decomposition, mold, or excessive moisture, it may be necessary to mix in dry materials occasionally. For standard use, you do not need to stir a worm bin.
Get the Best Worm Farm for Your Composting Needs
Food waste is a huge problem in the US right now, and gardeners can play a big part in solving it. By composting your own kitchen waste in worm farms, compost bins, and as ground fertilizers, you can drastically reduce what you send to landfill.
Even with climate impact put to one side, the financial benefits of worm farms are innumerable, making rich, multi-purpose compost and fertilizers from scraps that would be put in the bin otherwise. All you need to do now is choose the best worm farm for your garden.